A large crystal in a finer-grained matrix in a metamorphic rock: analogous to a phenocryst in an igneous rock.
Unusually large crystal contained in a finer crystalline matrix occurring in metamorphic rocks. The resultant texture is a porphyroblastic texture.... More
a mineral grain that grew in the solid state during metamorphism, enveloping and enclosing mineral grains that had formed previously
A large crystal formed during metamorphism; also known as a metacryst.
A porphyroblast is a large mineral crystal in a metamorphic rock which has grown within the finer grained groundmass as a result of static recrystallisation in the rock. Therefore porphyroblasts are almost always nice euhedral crystals.